Previous research has not suggested an increased risk of the cancer amongst IVF children.

Retinoblastoma is rare, occurring in around one in 17,000 births in Western countries.

Incidence

The Dutch research was carried out after the cancer was diagnosed in five children born after IVF, within 15 months of each other.

This researchers then compared these cases with the expected incidence of retinoblastoma in the normal population.

They estimated that children conceived by IVF could be between five and seven times more likely than non-IVF children to develop retinoblastoma.

Between 1% and 1.5% of Dutch babies are born through IVF, which is used to treat 3,000 women in the country each year.

It is small and it bases several figures on assumptions rather than real observations
Professor Christina Bergh, Sahlgrenska University Hospital, Gothenburg, Sweden

Dr Annette Moll, of the Vrije Universeit Medical Centre, said: "Whether treatment with ovulation-inducing drugs increases the risk of childhood cancer is an important matter, especially with the rising numbers…